US2451129A - Telemetering apparatus of the impulse-duration class - Google Patents

Description

Oct. 12, 1948. ye. M. THYNELL 2,451,129

TELEMETERING APPARATUS OF THE IMPULSE-DURATION CLASS Filedflarch 31, 1944 2 Sheets-Sheet l INVENTOR. W7

G. M. THYNELL Oct. 12, 1948.

TELEMETERING APPARATUS OF THE IMPULSE-DURATION CLASS Filed March 31, 1944 2 Sheets-Sheet 2 COLUMN 11 III III I I III III WINDING FIG. NO.

E=- ENERGIZED FIG. IO

'FIG. 9

Q FIG. 8

IN VEN TOR.

graduated scale.

Patented Oct. 12, 1948 TELEMETERING APPARATUS OF THE IMPULSE-DURATION CLASS Gustave M. Thynell, Naugatuck, Conn., assignor to The Bristol Company, Waterbury, Conn., a corporation of Connecticut Application March 31, 1944, Serial No. 528,846

Claims.

This invention relates to telemetrlc apparatus, and more especially to a receiving instrument adapted for use in telemetering installations operating upon the impulse-duration" principle of communicating signals to a conveniently located receiving instrument from a transmittinginstrument at a remote point. While there'are recognized a number of different systems of carrying out electrical telemetering, the method whose operation is based upon the transmission of impulses through an electrical circuit or channel is recognized as having many advantages. Since the required intelligence is transmitted through the medium of discrete impulses, and the only variable which is recognized by the receiving instrument is that of the time relation existing among said impulses, the circuit or channel may be of the type suited for simple telegraphy, and need not be provided with'the refinements which are necessary for a circuit or channel such as is used for speech communication or other purposes where there is required a precise modulation of the transmitted electrical magnitude.

The class of telemetering systems to which the present invention is especially applicable is that group known as the impulse-duration type; and the basic principles of this group are well shown in U. S. Letters Patent No. 1,822,683, granted to K. Wilde, September 9, 1931, and reissued a No. 19,039, January 2, 1934. In telemetering systems of this class impulses of variable duration are cyclically established in a telemetering circuit or channel. One end of each of the successive impulses may be established at a uniform interval in each of a series of succeeding cycles determined by isochronous action of the transmitting instrument, and the other end of each impulse is made to occur at an instant in the cycle depending upon the magnitude of the measured variable. Telemetering systems of the impulseduration group are widely used; and in the most commonly employed forms means are provided in the receiving instrument for translating the duration of the received impulse into a deflection of an exhibiting device, first in one direction and then in'the opposite direction with reference to a An example of a receiving instrument especially suited to this method of telemetering is found in U. S. LettersPatent No. 2,040,918 granted to C. W. Bristol, May 19, 1936; and an example of a transmitting instrument suited to use with said receiving instrument and with telemetering systems of the impulse principle in general is found in U. S. Letters Patent No. 2,214,159 granted to F. B.BIiStO], September 10, 1940.

While telemetering systems of the impulse type in which the positioning of the receiving element is determined solely by the duration of each impulse transmitted through the interconnecting circuit'are capable of a high degree of precision, yet the function of positioning of the pointer or index of the instrument is carried out for only a relatively short portion of the cycle of operation, and during the remainder of the cycle this function is lost and the positioning mechanism may be said to be inert.

It is an object of the present invention to provide in telemetering systems of the impulse-duration class a receiving instrument which in comparison with previous types, will act for a greater part of each cycle to perform its function of positioning the indicating or recording pointer.

It is a further object to provide an instrument of the above class in which th shifting of the pointer from one position .to another will be carried out in response to increments or changes in the durations of successive impulses, rather than to the actual durations of said impulses.

It is a further object to provide, for use in conjunction with a transmitting telemetering instrument adapted solely to define the durations of successive cyclical impulses in correspondence with successive Values of a measured variable and to transmit said impulses over a two-conductor circuit, a receiving instrument incorporating in a single unit both the function of response to said impulses and also of response to increments between impulses in successive cycles.

It is a further object to provide a receiving instrument of the above class in which the positioning means shall be equally active in both directions and will respond both to changes in intervals during which an electrical impulse is impressed upon the receiving mechanism and intervals in which no impulse is being received from the transmitting circuit.

It is a further object to provide a receiving instrument of the above class in which the positioning action taking place in each cycle of operation shall take cognizance of the position in which the index, pointer, or other exhibiting member, was left by the effect of impulses occurring in previous cycles of operation.

having two sources of power therein, one being a continuously operating motor adapted to actuate either of two timing elements whereby there are developed time intervals to be compared with similar intervals transmitted from a remotely located measuring instrument, and the other a reversible motor adapted to position an index or pointer through increments whose durations are determined on the basis of said comparison.

In the drawings: 7

Fig. 1 is a diagrammatic representation of a telemetering receiver embodying the principles of the invention, and showing both the mechanical elements and the electrical relays and circuits by which various combinations of connections are set up in order to effect performance of the apparatus.

. means of a resilient spring 35, but adapted, when Fig. 2 is 'an end elevation of the pointer and scale forming elements of the device shown in Fig. 1.

or de-energized conditions of certain electric windings forming elements of the invention.

Referring now to the drawing:

Journaled in bearings ill and II upon a base plate I2 is an extended shaft member i3 adapted for rotation through a limited angle about its axis and carrying an extended pointer or index i4, which, in cooperation with a graduated, stationary scale l5, provides a measure of the angular position of said shaft. A reversible motor l6, preferably of the synchronous clock type, and having two windings l1 and i 8 whose respective energization from a suitable source of electric power will determine the direction of rotation, is operatively connected to the shaft l3, as by a gear train IS. The arrangement of the motor windings is such that energization of the winding II will cause the shaft l3 to be rotated in a clockwise direction as seen in Fig. 2, and as indicated by the arrow A in Fig. 1, while energization of the winding 18 will cause the shaft to be rotated in the reverse direction. The angular velocity being the same, in either direction rotation.

Mounted upon the shaft i3 and rotatable therewith is a contact assembly having two mutually insulated spring-engaged contact members 20 and 2i (more clearly shown in Fig. 3), the latter projecting'for engagement whereby upon the application thereto of a force in a direction corresponding to clockwise rotation of the shaft i3, said contacts will be separated, with resultant opening of an electrical circuit therebetween. Also carried by the shaft i3, but freely rotatable with respect thereto, is a hub member 22 having a radially extending arm 23 carrying a tappet screw 24, said arm normally being urged toward, and retained in engagement with, a fixed stop 25 by means of a resilient spring 26, but adapted, when rotated about the axis of the shaft l3 in a sense corresponding to the arrow B in Fig. 3, to carry the tappet screw 24 inengagement with the contact member 2|, causing the contacts 20-2i to be separated.

rotated about the axis of the shaft l3 in a sense opposed to the arrow A, to carry the tappet screw into engagement with the contact 3| causing the contacts 30-4! to be separated.

Attached to the hub member 22 is a clutch element consisting of a flat plate 40 having there on a facing of friction material 4| such as sheet cork or rubber. Carried by the shaft II and freely rotatable with respect thereto and also free for limited axial translation thereon, is a further clutch element including a hub member 42 carrying a flat plate 43 having a facing of friction material 44 juxtaposed to the friction facing of the plate 40. member 42 is a flange 45 engaged by a rockable bell-crank 46 pivotally mounted upon the base plate l2 and having a bifurcated extremity 41 whereby, uponangular displacement of the bellcrank 46 about its pivotal mounting the hub member 42 and parts .carried thereby will be axially displaced along the shaft l3, bringing the friction surfaces of the respective clutch elements into engagement, rendering said elements rotatable as an. integral unit.

Attached to the hub member 32 is a clutch element consisting of a flat plate 50 having-thereon a facing of friction material similar to that on the plate 40. Carried by the shaft l3, and freely rotatable and translatable with respect thereto, is a further clutch element including a hub member 52 carrying a fiat plate 53 having a facing of friction material juxtaposed to the sim-' ilar facing of the plate 50. Attached to the hub member 52 is a flange 55 engaged by a'rockable bell-crank 56 pivotally mounted upon the base plate 42 and having a bifurcated extremity 51 whereby, upon angular displacement of the bellcrank 56 about its pivotal mounting, the friction surfaces of the respective clutch elements will be brought into engagement, rendering said elements rotatable as an integral unit.

Fixed to the hub member 52 is a gear 59 adapted to rotate said hub member together with clutch element 53 carried thereby upon the shaft i3, and also to be translated through a short distance axially of said shaft as said hub memher is moved by operation of the bell-crank 56. Journaled in bearings 60 and Bi is a shaft 62 disposed parallel to the shaft l3, and having fixed thereto a gear member 63 meshing with the gear member 59, whereby rotation of the shaft 62 will :be imparted to the hub member 52 and parts carried thereby. Fixed to the hub member 42 is .a gear member 64'; and a gear 65 is attached to Attached to the hub stant velocity, so that the clutch elements carried by the hub members 41 and 52 respectively will be rotated in opposite directions. The ratios of the several gear members are so selected that the rotary motions imparted to the hub members 42 and 52, while opposite in sense, will have equal angular velocities, preferably, though, as will hereinafter be set forth, not necessarily, the same as the angular velocity imparted to the shaft is by operation of the motor l6.

Associated with the mechanism on the baseplate 12, in a manner presently to be explained, are nine relays, each having an actuating winding, and with con-tact arrangements which may be designated asiollows:

A relay 8i is provided with four sets of contacts 8la and Bib normally open, and Bic and Bid normally closed.

A relay 82 is provided with two sets 0! contacts 82a and 827), both normally open.

A relay 83 is provided with contacts 33a normally closed, and 83b normally open.

A relay 84 is provided with two sets of contacts 84a and 842) both normally open.

A relay 85 is provided with contacts 85a normally closed and 35b normally open.

A relay 86 is provided with contacts 860. normally open and 86b normally closed.

A relay Bl is provided with contacts ills, dlh,

and 81c normally closed, and did normally open.

A relay 38 is provided with contacts 88a and 88b normally closed, 880 normally open, and 38d normally closed.

A relay 89 is provided with contacts 89a normally closed and 89b normally open.

In addition to the electrical contact members above set forth, the relays 82 and 84 are mechanically linked to the bell-cranks ii and 58 respectively, so that energization of the winding of the former relay will actuate the bell-crank 46 in a sense to translate the hub 52 and parts carried thereby along the shaft i3. causing the friction surfaces of the associated clutch elements to be engaged, whereby rotary motion imparted to the gear member 66' will be imparted to the tappet arm 23, and energization of the winding of the latter relay will similarly cause the clutch elements associated with the hub member 52 to be engaged, and motion of the gear 59 to be imparted to the tappet arm 33.

Associated with the elements hereinbefore set 'forth, and adapted to function as a source of impulses for operating the same, is a transmitting instrument 90 preferably of the class fully set forth and described in U. S. Letters Patent No. 2,214,159 granted September 10, 1940 to F. B. Bristol. This instrument comprises a measuring element 9| having a defiectaole arm 52 adapted to excurse across the face of a conrtinuously rotating spiral plate 53 and to be periodically engaged'nnd released thereby, thus causing a contact member 94 to be actuated and to establish cyclically recurrent time intervals whose successive durations will be representative of successive values of the magnitude measured by the element St. As the principle and construction of the impulse-generating instrument is fully described in said F. B. Bristols patent, and as said instrument is taken only as an example of that general class of telemetering transmitters operating on the impulse-duration principle, it will not here be necessary to describe the device in further detail.

While to those conversant with the art of electrical control, it will be obvious that the Ivar-ions elements of the apparatus may be energized from more or less independent electrical sources, they are hereinafter for purposes of simplicity'described as all receiving electric power from a. common source Hi0, as represented by a two wire circuit having individual conductors or buses Ill and I02, between which is maintained an electrical potential or voltage and rrequency to the utilization of which all the electro-responsive elements of the apparatus are adapted. To the conductor IOI is connected one side of each of the motor windings i1. i8, and N, and one side of each of the relay contacts Ola, Bib, Bic, did, 820, and 84a, as well as one side of the contacts 94 in the instrument 90. To the conductor in are connected one side of each of the actuating windings of relays 8!, 83, 35, 88, and 89, the mechanically actuated contact members 2i and at; one side of each of the relay contacts 86a, 86b, 91c, and Zi'ld, and also the free terminals of the'motor winding st.

A conductor M3 provides interconnection between the free terminal of the relay contacts 31a, and one side of each of the contacts 83c and 88a; and a conductor w ll similarly provides interconnection between the free terminals of the relay contacts irl and one side of each or the contacts 8% and 3%, the free terminals of said lastnamed contacts and of the winding oi relay 35 being interconnected by means of a conductor W6.

A conductor idfi provides interconnection between the free terminals of relay contacts tit; and one side of the contacts 82b and are, the free terminals of said last-named contacts and of the winding of the relay 83 being interconnected by means oi a conductor 501. A conductor 08 provides interconnection between the free terminal of the relay contacts Bio and one side of each of the contacts a and 81a. A conductor I05 provides interconnection between the free terminals of contacts 82a and 83a and one side of the relay winding 82 and of the relay contacts 88b. A conductor iii! provides interconnection between the free terminals of relay contacts 84a and 85a and one side of the relay winding 34 and the relay contacts 81b. The free terminals of relay contact 8gb and one side of the actuating winding of relay 81 are interconnected by means of a conductor ill; and the free terminals of relay contact 81b and one side of the winding of relay 8! are similarly interconnected by means of a conductor H2. A conductor H3 provides interconnection between mechanically actuated contact member 20 and the free terminals of the windings of relays 82 and 81; and a conductor 5 i4 similarly provides interconnection between the mechanisally actuated contact member 30 and the free terminals of the windings of relays B4 and 88.

A conductor iii provides interconnection between the free terminal of the winding ll of the motor is and one side of each of the relay contacts 88c and 89a; and a conductor H6 similarly provides connection between the free terminal of the winding i8 of said motor and one side of each of the contacts 88d and 891). A conductor H'I provides interconnection between the free terminals of contacts 85c, 81c, 88c, and 89a; and a conductor H8 similarly provides interconnection between the free terminals of contacts 8612, Old, 88d and 85b. A conductor H8 provides connection between the free terminal of contact 88a and of the winding of relay 85; and a conductor are similarly provides connection between the tree terminal of contact 81a and of the winding of relay 88.

will be made clear in the course of the explanation, .th'ere can at no time exist an operating condition in which all relaysarede-energized. Fig. 4, therefore, which represents the contact combination under such a condition, is I provided merely as a basis of reference in studying the 110 combinations shown in the figures which follow. A conductor I2I provides connection between the free terminal of the winding of the relayli and that of the contact member in,.the transmitting instrument 80. In the application of the invention to the practice of telemetering, where the transmitting instrument 80 will be located at apoint of measurement rcmotefrom the receiving apparatus, the conductor III, in conjunction .with that portion of the line conductor ml which is connected to the contact member 84, will serve as a two-wire channel, through which impulses originating with the contact member 84 may be transmitted to the receiving mechanism. v

a For the purpose of explaining the operation of the invention, it may be assumed that the shaft I8 and parts carried thereby occupy a position of rest with thepointer I4 intermediate the extremities of the scale I8 and having an excursion representing the resultant of previouslyimparted impulses; and that the spiral plate 88 of the transmitting instrument is in rotation at a uniform velocity, engaging and disengaging the arm 82 to close and open the contact member 84 cyclically, and that the connection is such-that an increasing value of the magnitude measured .by the element 9| will tend to increase the proportion of the operating cycle during which the contact member 84 is in a closed condition. and vice versa. Assuming now, that the source I00 is energized, making the conductors IN and I02 the two sides of an electrical circuit; consideration may be given to conditions developing with such energization first taking place with the contact member 84 in closed position.

Both sides of the circuit, as represented by the conductors I'0I and I02, being connected to the winding 69 of the motor 68, said motor will operate continuously, causing the shaft 02 to rotate in a direction as indicated by the arrow C, the gear 63 carried by said shaft coacting with the gear 59 todrive the same and the associated clutch member in an angular sense opposed'to that indicated by the arrow A. At the same time, the gear acting through the idler 65 will cause the gear 64 and its associated clutch element to be driven in the sense indicated by the arrow A Contact member 84 in the transmitting instrument 'being closed, the relay 8| will be energized, with its contacts 8Ia and Bib closed and Me and lid open. Contact 8Ia will provide a path be tween line conductor I M and conductor I03, and thence through normally closed contacts 88a and the winding of relay 86 to line conductor I02,

causing said last-named relay to be energized,

closing contact 86a and opening contact 86b. Normally closed contact 83a will provide a path from conductor I03 to conductor I08, and thence through the winding of relay 82, conductor I I 3, mechanically-actuated contacts 202 I,-. to line conductor I02, thus causing the relay 82 to be energized, closing its contacts 821: and 82b, and incidentally actuating the bell-crank 46 to engage the friction faces of the clutch members 40 and 03, whereby the tappet arm 23 will immediately begin I "to rotate from its normal position of rest against the stop 28 in a direction. indicated by arrow A.

' At the same-time, the closing of the contact 02!) will provide a path between the conductors I08 and. I0! in parallel with the contact 83b; Connection between conductors I08 and III will be established by the normally closed contact 88b, whereby apath is provided through the winding ofrelay 81, conductor I I8, contacts 20-2 I, to line conductor. I02, thus causing relay 8! to be energized, opening its contacts 81a, 81b, and "c and closing contact 81d. Relay contact 8": places line conductor IOI directly in connection with conductor I05. The now closed contact 88:: provides connection between line conductor I02 and conductor 1,. and thence through normally closedcontact 88a to conductor I I5 and the winding I! of the motor iii to line conductor IOI, causing said motor to be energized in a sense tending to rotate the shaft I8 and the pointer I4 carried thereby in a'direction indicated by the arrow A, such rotation, however, being inhibited by an opposing influence derived from the motor winding I8 in the following manner: I

The relay 8! being energized, and its contact 81d closed, there is provided a path from line conductor I02 to conductor II8, through normally closed contact 88d to conductor. H8, and thence through the winding I8 of the motor I8 to line conductor IOI, causing said motor to be energized in a sense opposed to the influence of winding II, thus stalling the motor with dynamic the tabulation of Fig. 11, will be maintained until either of two conditions is fulfilled, depending upon whether the contact 84 is maintained in a closed position for a shorter or a longer interval than that represented by the previousexcur'sion of the shaft I3, and thus upon whether said con- .tact 84 is opened before or after the tappet 28 has had time to reach the position occupied by the contact member Z-I. k Assuming thatthe value of the measured magnitude isless than that at the time of the preceding cycle as determined by the rotation of the spiral plate 93 in the instrument and as represented by the excursed position of the shaft II and .elements carried thereby, the contact, 84 will be maintained in a closed condition for a shorter time than in said preceding cycle, opening before the tappet 23 in its excursion can reach the position occupied by the contact member 2I, and causing the relay 8i to be de-energized, opening its contacts III a and 8Ib and closing its contacts ale and 8Id. Since the contact Qla "is shunted by contact 82a, its opening will have no immediate effect upon circuit conditions, other than to lie-energize relay 86. Opening of contact Bib, however, will cause relay 83 to he de-energized. closing its contact 83a and opening its contact 83b. Closing of the contact 8Ic will establish a path from conductor IM to conductor I08 throug-hcontactBSa to conductor I I0, through the winding of relay 84 and the normally closed contact members 30--3I to conductor I02, whereby relay 84 will be energized, contacts 84a and 84b tor llll to conductor I04, and thence through contact 841), conductor I06 and relay 35 to conductor I02, energizing said relay 85, which will open the contact 85a and at the same time lock in the relay through the shunting of contact 841) by contact 85b. The positions of the several relays will now be as indicated in column II of the tabulation, and the combination of contacts immediately associated with the circuits of the motor i6 will be as indicated in Fig. 6, the winding it being energized and the winding il tie-energized, causing the motor to rotate the shaft l3 and the parts carried thereby in a sense opposed to the arrow A and to reduce the reading of the pointer or index l4 with respect to the scale l5. At the same time the contact assemblies .2B--2l and 3i!3l are being carried around by the shaft l3, and both tappet arms 23 and 33 are being rotated about the shaft the former in opposition to, and the latter in the same direction as, the rotation of said shaft.

The mutual approach of contact member 2i and tappet 24 due to their rotations in opposite directions will tend to bring them into engagement; and since the contact 9% will remain open for a longer interval than in the preceding cycle, such engagement will take place, with resultant separation of the contacts 28-2i, at a point intermediate the former position of the contact 2i and the position attained by the tappet 24 at the moment the contact 94 was opened and the shaft i3 started on its rotation. Separation of contacts 20 -2 will open the circuit between them, thus de-energizing relay 82 and thereby opening its contacts 82a and 82b and also releasing the clutch elements Iii-i3 from mutual engagement, whereby the tappet arm 23 under the influence of spring 26 will immediately be reset to its normal position of rest against the stop 25. The opening of contacts 20-2! will also decnergize the relay 81, thus closing contacts 87a, 81b, and 810 and opening contact 87:2. The closing of contact 81a will provide path from conductor I08 to conductor I20 and thus through the winding of relay 89 to conductor E02 energizing said relay. The closing of contact 812) will provide a path from conductor l0i through the closed contact 84a and conductors l Iii-I l2 through the winding of relay 88 to conductor H4 and the normally closed contacts 3i32 to conductor I02, energizing relay 88. The positions of the several relays will now be as indicated in column III of the tabulation, and the combination of contacts immediately associated with the circuits of motor IE will be as indicated in Fig. 7, so that said motor will be brought to rest with dynamic braking due to the opposed influences of windings i1 and I8.

The position in which the motor l6, with its driven shaft l3 and elements carried thereby is brought to rest will depend upon the duration of the impulse imparted thereto; and this will represent a time interval determined by the original position of the contact member 2| in the cycle of operation and by the delay of the starting of the tappet arm 23 from its rest position subsequent to the beginning of motion of the shaft 13. In other words, said interval will be determined in part by the time elapsing between closing and opening of the contact 94, and in part by the position assumed by the shaft (3 in the previous cycle of operation; and the pointer M will have tended to move down scale from its previous position a distance represented by the decrease in duration of the contact interval of the contact member 94 as compared with the interval representing the previously attained position of the pointer M, which distance, of course, is in turn representative of the decrease in value of the measured magnitude below that determined in the previous cycle of operation.

The relay 84 bein energized, and the tappet arm 33 advancin toward the position attained by the contact member 3i, it is obvious that engagement between said contact member and the tappct 34 will, or will not, take place, according to whether the interval of open circuit at the contact 84 is longer or shorter than that required for said tappet arm to excurse from its position of rest against the stop 35 to the position occupied by the contact member 3 i.

If said contact member has not attained a position corresponding to the measured magnitude it will be engaged'by the tappet 34 before the contact 94 in the instrument 90 is again closed. Immediately upon such engagement the contacts Lil-30 will be separated, de-energizing the relay 84 and allowing the tappet arm 33 under the influence of the spring 36 to reset to its position of rest on the stop 35. While the release of relay 84 will open its contacts 84a and 841), this will not affect the performance of the apparatus, as contact 84a is shunted by a path through contact 8lc and associated conductors, and contact 84b is shunted by contact 8522. Separation of contacts 303i will, however, de-energize the relay 88, with the result that the several relays will now have assumed the positions indicated in column IV of the tabulation. The function of contact 85a, which is held open due to energization of the relay 85, is to interrupt the connection between conductor I08 and relay 84, whereby said relay 84 will not be re-energized by the closing of contacts 30-3! upon their release by the tappet 34. arrangement of contacts directly associated with the motor circuits will now be as shown in Fig. 8, and the motor IE will be operating in a sense to move the shaft l3 and elements carried thereby in a direction opposite to that indicated by the arrow A. This condition will continue until the contact 84 is again closed due to rotation of the spiral plate 93, whereupon relay 81 will be energized, de-energizing the circuits to relays 89 and 85, and re-establishing conditions as they were at the beginning of the cycle of operation, whereby the relays will assume the positions indicated in column V of the tabulations (which is identical with column I), and the motor IE will be brought to rest with dynamic braking while the tappet arm 23 is advancing from its normal rest position.

It will be seen that during the cycle described, the indicating pointer M has received two distinct impulses representative of the change in the value of the measured magnitude from that determined during the previous cycle, the first of these impulses being determined by the excess of the deflection over the value of the measured quantity, and the second by the deficiency of the deflection as measured from the top of the scale as compared to the amount by which the measured magnitude falls short of the full-scale reading of the instrument. From the foregoing it will be seen that if the angular velocity of the tappet arms is the same as that of the shaft l3, a true indication of the value of a decreasing magnitude will be attained on the second half cycle of operation. If the angular velocity of the tappets is less than that of the shaft [3, then on a decreasing magnitude a relatively 11 closer approach to the true indication will be attained on the first halt cycle, and the instrument will overshoot into the low scale end on the second half cycle. Successive half cycles will find the instrument overshooting by the samev percent as the amount of overshoot in the second half cycle but if the percentage overshoot is less than 100, the instrument will in successive half cycles approach the true reading-the actual deviation therefrom becoming smaller with each half cycle. If on the other hand, the angular velocity of the tappets is greater than that of the shaft l3, a relatively small approach to the true indication will be made on the first half cycle, and on the second half cycle the index will fall short of the true reading. In the succeeding half cycles of operation the tendency will be to correct any deviation thus developing, so that within several cycles, even though there be a discrepancy between said angular velocities, a correct reading will be obtained.

The operation of the device under conditions of increasing value of the measured quantity is in all respects similar to that set forth for decreasing values, and may be briefly outlined as follows: Assuming first that the contact 94, as before, closes at a definite and invariable point in the cycle of operation, there will be set up a combination of relays corresponding to column I of the tabulation in Fig. 11, and of the motor control contacts as shown in Fig. 5, whereby the motor 18 will be locked in a position of rest, with the tappet arm 23 approaching the contact member 2i.

As the measured quantity has increased over the value determined in the previous cycle of operation, it follows that the'contact 94 will be maintained in a closed position for a longer time than in said previous cycle, while the excursion of the tappet arm 23 necessary for the tappet 24 to engage the contact member II will occupy only a time corresponding to the previously established position of said contact member, with the result that the contacts 2ii-2i will be separated while the contact 94 remains closed.

Opening of the contacts Iii-II will de-energize relays 82 and 81, whereby the tappet arm 23 will be released and will reset to its stop. Contact 82a will be opened, but, being shunted by the circuit through contact 8ia, will produce no immediate effect on operation. Similarly, the

opening of contact 82b, which is shunted by con tact 83b, will produce no immediate eflect. The several relays will now have assumed positions indicated in column VI of the tabulations, and the motor control contacts will be as shown in Fig. 9, whereby the winding i8 is deenergized, and the motor, under the unopposed influence of winding i! will cause the pointer l4 to be advanced in an up-scale direction.

After a further lapse of time corresponding to the increment of duration of the impulse established by the contact 94 over that determined by the previously attained setting of the contact member 2|, the contact 94 will be opened, deenergizing the relay 8i, opening its contacts Ma and Nb and closing its contacts lie and lid.

Relays 83 and 83 will be de-energized. The closing of contact Bic will provide a current path through closed contact 81a, to energize relay 89, and through contact 85a to energize relay 84, and also through contact 87b to energize relay 88. The closing of contact 8id will provide through contact 84b a current path to energize relay 8!. The several relays will now have .5-

will be as shown in Fig. 7, wherein both windings l1 and i8 are energized and the motor l8 brought 5 to rest with dynamic braking. As the interval.

of time during which the motor It was energized represents the increment of the measured I quantity over its previously determined value, it will be obvious that the pointer I4 will have been advanced a correspondingdistance along the scale i5, and will have approached an indication of the newly attained value.

At the same instant as the motor l6 was brought to rest, the engagementof the clutch elements 50-53, due to energization of the relay 84, will have started the tappet arm 33 advancing from its normal position of rest against the stop 35 to that occupied by the contact member 3i. If, for any reason, such as acceleration characteristics of the motor i6 or delay in operation of relays, the pointer l4 has not fully attained a position corresponding to the true value of the measured magnitude as communicated by the impulse determined by the contact 94 in the transmitting instrument, the time interval required for the tappet arm 33 to travel to the position occupied by the contact element 3| will be greater than the interval between the opening of the contact 94 and its reclosing by engagement of the pointer-arm 92 with the leading edge of the plate 93, so that, as relay 8! is energized by closing of the contact 84, the contact elements 3l will still be in engagement, retaining relays 84 and 88 in an energized condition. Opening of relay contact 8ic will deenergize relay 89, and opening of contact 8id will deenergize relay 8-5; but because relays 84 and 88 remain energized, this will have no immediate eflect on circuit conditions. The several relays will now have assumed positions indicated in column VIII of the tabulation in Fig. 11, and the motor control contacts will be as shown in Fig. 10, wherein winding l8- of the motor I6 is deenerglzed, allowing the winding I! to exert its influence without opposition, and further advance the pointer i4 toward a position representing the true value of the measured quantity.

Energization of the relay 8i will have caused the relay B2 to be energized, whereby tappet arm 23 will have started to excurse; but becaus of contacts 88a and 88b being open, due to energization of relay 88, this part of the circuit will have no present effect on performance of the motor i8. The contact assembly 30-3 I, carried by the shaft I3 will have started to excurse with said shaft in a sense to meet the tappet arm 33 which will still be approaching the position held by the contact element 3! at the conclusion of the previous setting impulse. As the tappet 34 engages the contact element 3i, momentarily separating it from the contact element 30,- the relay 84 will be de-energized, opening its contacts 84a and 84!), causing the tappet arm 33 to reset to its normal position-0f rest. At the same time, relay 88 is de-energized, thus closing its contacts 88a and 88b, and energizing relays 86 and 81, whereby the several relays in the system will have reverted to the conditions in column I of the tabulation,

and the motor control contacts to the arrangement shown in Fig. 5, bringing the motor to rest with dynamic braking, and establishing conditions for a succeeding cycle, which was actually initiated at the moment the tappet arm 23 began its excursion in response to energization of the relay 82 when the contact 34 in the transmitting instrument 90 was closed by engagement of .the arm 82 with the leading edge of the spiral plate 93.

For an increasing value of the measured quantity, the characteristic operation of the apparatus with respect to relative velocities of the shaft 13 and the tappet arms will be similar to that described in connection with a decreasing value. If the angular velocities are equal, a true indication of the measured magnitude will be obtained on the first half cycle of operation. If the velocity of the shaft 83 is greater than that of the tappets, the instrument will overshoot on the first half cycle, and on the second half cycle will also overshoot but in reverse direction by a proportion equal to that of the overshoot on the first half cycle. If the overshoot is less than 100% the instrument will in successive half cycles approach the point of balancethe deviation becoming smaller with each half cycle. If on the other hand, the speed of the shaft i3 is less than that of the tappets, the instrument will approach true indication on the first half cycle and in successive half cycles will continue to approach true indication until quilibrium is reached. It will thus be obvious that lack of synchronism between the motors in the transmitting and the receiving instruments will have no ultimate effect upon the accuracy of the readings of the latter instrument with respect to measurements performed by the former.

Th terms and expressions which I have employed are used as terms of description and not of limitation, and I have no intention, in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but recognize that various modifications are possible within the scope of the invention claimed.

I claim:

1. In a telemetric receiver adapted to respond to cyclically transmitted electrical impulses each of a duration corresponding to a value of a variable, the combination of an element settable to positions corresponding to values of said variable,

clutch means, continuously operable motor means,

means for engaging said clutch means with said motor means in response to the beginning of an impulse for efiecting operation of said clutch means in a given direction, other clutch means, means for engaging said other clutch means and said motor means in response to termination of said impulse for eifecting operation of said other clutch means in the opposite direction, contact means controlled by the respective clutch means, and reversible motor means controlled by said contact means for ositionin said element.

2. In a telemetric receiving instrument adapted to respond to cyclically recurrent impulses corresponding to values of a variable, the combination of a rotatable shaft, an element rotatable with said shaft to positions representative of values of said variable, a reversible motor operatively connected to said shaft and adapted to position the same, contact members carried by said shaft and movable therewith, contact actuating members carried by said shaft and freely rotatable thereon and adapted to cooperate respectively with said contact members, spring means asosciated with said contact actuating members to urge the same in opposite angular senses respectively and normally maintaining them against fixed stops, independently operable clutch means for impelling said contact actuating members about said shaft in directions opposed to the influences of their respectively associated spring means, means for actuating said clutch means in response to said cyclically recurrent impulses, and means to render said clutch means inactive upon coaction of respectively driven contact actuating members with corresponding co operating shaft-carried contact members together with means responsive to said impulses and rendering said reversible motor operative and means responsive to the coaction of said contact actuating members and said contact members for rendering said motor inoperative. I

3. In a telemetric receiving instrument adapted to respond differentially to the initiations and the terminations of cyclically recurrent electrical impulses corresponding to values of a variable, the combination of a rotatable shaft, an element rotatable with said shaft to positions representative of values of said variable, a reversible electric motor operativeiy connected to said shaft and adapted to position the same, two contact members carried by said shaft and movable therewith, two contact actuating members carried by said shaft and freely rotatable thereon and adapted to cooperate respectively with said contact members in controlling an electric circuit, spring means associated with said contact actuating members to urge the same in opposite angular senses respectively and normally maintaining them against fixed stops, independently operable clutch means for impelling said contact actuating members about said shaft in directions opposed to the influences of their respectively associated spring means, electromagnetic means responsive to the initiations of said impulses and actuating one of said clutch means for impelling a corresponding one of said cont act actuating members about said shaft in a direction opposed to the influence of the associated spring means, electromagnetic means responsive to terminations of said impulses for similarly actuating the other of said clutch means, and means responsive to conditions in said electric circuit for deenergizing said electromagnetic means and thereby rendering said clutch means inactive upon engagement of a respectively driven contact actuating member with the corresponding cooperating shaftcarried contact member, together with separate relay means responsive to the initiations and terminations of said impulses to render said motor operative in corresponding directions, and other relay means responsive to the engagement of said contact actuating member with the corresponding contact member for rendering said motor inoperative.

4. In a telemetric receiver adapted to respond to cyclically transmitted electrical impulses defining in each cycle a time interval corresponding to a value of a variable, the combination of an element settable to positions corresponding to values of said variable, relay means responsive to said impulses and energized in each cycle for a time duration corresponding to the value transmitted during said cycle, reversible motor means for positioning said element, contact means movable with said element, means for actuating said contact means, other contact means movable with said element, means for actuating said other contact means, a, relay brought into action by operation of said relay means at the beginning of said interval for causing the first mentioned actuating means to actuate the first mentioned contact means at the end of an interval dependent upon the position of said element, another relay brought into action by operation of said relay means at the end of said interval for causing the 5. In a telemetric receiver adapted to respond to cyclically transmitted electrical impulses defining in each cycle a time interval corresponding to a value of a variable,- the combination of an element settable to positions corresponding to values of said variable, relay means responsive to said impulses and energized in each cycle for a time duration corresponding to the value transmitted during said cycle, reversible motor means for positioning said element, contact means movable with said element, means for actuating said contact means, other contact means movable with said element, means for actuating said other contact means, a relay brought into action by operation of said relay means at the beginning oi. said interval for causing the first mentioned actuating means to actuate the first mentioned contact means at the end of an interval dependent upon the position of said element, another relay brought into action by operation of said relay 18 means at the end of said interval for causing the second mentioned actuating means to actuate the second mentioned contact means at the end of an interval dependent upon the position of said element, and relays controlled by the afore-' mentioned relays for controlling said reversible motor, the last mentioned relays comprising relays energized concurrentl with the first mentioned relays, and other relays controlled by contacts of said concurrently energized relays.

GUSTAVE M. THYNEIL.

REFERENCES The following references are 0! record in the file of this patent:

UNITED s'ra'rss PATENTS Orlich Sept. 11, 1945

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